Craven & Lee (2006) determined that DDP is a supported and acceptable treatment (category 3 in a sixlevel system). However, their review only included results from a partial preliminary presentation of an ongoing follow-up study, which was subsequently completed and published in 2006. This initial study compared the results DDP with other forms of treatment, ‘usual care’, 1 year after treatment ended. A second study extended these results out to 4 years after treatment ended. Based on the Craven & Lee classifications (Saunders et al. 2004), inclusion of
those studies would have resulted in DDP being classified as an evidence-based category 2, ‘Supported and probably efficacious’. Other than lacking two randomized controlled studies, DDP would have be classified as a category 1, "Well supported efficacious treatment," the highest level.
The interested reader may want to look at the following references for further details:
Becker-Weidman, A., (2006)“Treatment for Children with Trauma-Attachment Disorders: Dyadic Developmental Psychotherapy,” Child and Adolescent Social Work Journal. Vol. 23 #2, April 2006, pp 147-171.
Becker-Weidman, A., (2007) “Treatment For Children with Reactive Attachment Disorder: Dyadic Developmental Psychotherapy,” http://www.center4familydevelop.com/research.pdf
Becker-Weidman, A., & Hughes, D., (2008) “Dyadic Developmental Psychotherapy: An evidence-based treatment for children with complex trauma and disorders of attachment,” Child & Adolescent Social Work, 13, pp.329-337.Becker-Weidman, A., & Shell, D., (Eds.), (2008) Creating Capacity for Attachment: Dyadic Developmental Psychotherapy in the Treatment of Trauma-Attachment Disorders. Arthur Becker-Weidman, Ph.D., & Debra Shell, (Eds.) Woods N Barnes publishing,
Craven, P. & Lee, R. (2006) Therapeutic interventions for foster children: a systematic research synthesis. Research on Social Work Practice, 16, 287–304.
Saunders, B., Berliner, L. & Hanson, R. (2004) Child physical and sexual abuse: guidelines for treatment. Available at: http://academicdepartments.musc.edu/ncvc/resources_prof/